/* GNU Objective C Runtime Thread Implementation for PCThreads under Linux.
- Copyright (C) 1996 Free Software Foundation, Inc.
+ Copyright (C) 1996, 1997 Free Software Foundation, Inc.
Contributed by Scott Christley <scottc@net-community.com>
This file is part of GNU CC.
* provided by the system. We augment it with depth and current owner id
* fields to implement and re-entrant lock.
*/
-struct _objc_mutex
+struct objc_mutex
{
- volatile _objc_thread_t owner; /* Id of thread that owns. */
+ volatile objc_thread_t owner; /* Id of thread that owns. */
volatile int depth; /* # of acquires. */
pthread_mutex_t mutex; /* PCThread mutex */
};
+struct objc_condition
+{
+ pthread_cond_t condition; /* cthread condition */
+};
+
/********
* Initialize the threads subsystem. Returns 0 if successful, or -1 if no
* thread support is available.
* Create a new thread of execution and return its id. Return NULL if fails.
* The new thread starts in "func" with the given argument.
*/
-_objc_thread_t
+objc_thread_t
objc_thread_create(void (*func)(void *arg), void *arg)
{
- _objc_thread_t thread_id;
+ objc_thread_t thread_id;
pthread_t new_thread_handle;
objc_mutex_lock(__objc_runtime_mutex);
if ( !(pthread_create(&new_thread_handle, NULL, (void *)func, arg)) )
{
- thread_id = *(_objc_thread_t *)&new_thread_handle;
+ thread_id = *(objc_thread_t *)&new_thread_handle;
__objc_runtime_threads_alive++;
}
else
objc_thread_set_priority(int priority)
{
/* Not implemented yet */
- return -1; /* Failed. */
+ return -1; /* Failed. */
}
/********
objc_thread_get_priority(void)
{
/* Not implemented yet */
- return OBJC_THREAD_INTERACTIVE_PRIORITY; /* Highest priority. */
+ return OBJC_THREAD_INTERACTIVE_PRIORITY; /* Highest priority. */
}
/********
__objc_runtime_threads_alive--;
objc_mutex_unlock(__objc_runtime_mutex);
- pthread_exit(&__objc_thread_exit_status); /* Terminate thread. */
+ pthread_exit(&__objc_thread_exit_status); /* Terminate thread. */
return -1;
}
* Returns an integer value which uniquely describes a thread. Must not be
* NULL which is reserved as a marker for "no thread".
*/
-_objc_thread_t
+objc_thread_t
objc_thread_id(void)
{
pthread_t self = pthread_self();
- return *(_objc_thread_t *)&self; /* Return thread handle. */
+ return *(objc_thread_t *)&self; /* Return thread handle. */
}
/********
* Allocate a mutex. Return the mutex pointer if successful or NULL if the
* allocation failed for any reason.
*/
-_objc_mutex_t
+objc_mutex_t
objc_mutex_allocate(void)
{
- _objc_mutex_t mutex;
+ objc_mutex_t mutex;
- if (!(mutex = (_objc_mutex_t) objc_malloc(sizeof(struct _objc_mutex))))
+ if (!(mutex = (objc_mutex_t)objc_malloc(sizeof(struct objc_mutex))))
return NULL; /* Abort if malloc failed. */
/* Create PCThread mutex */
* Returns the number of locks on the thread. (1 for deallocate).
*/
int
-objc_mutex_deallocate(_objc_mutex_t mutex)
+objc_mutex_deallocate(objc_mutex_t mutex)
{
int depth; /* # of locks on mutex. */
* Returns the lock count on the mutex held by this thread.
*/
int
-objc_mutex_lock(_objc_mutex_t mutex)
+objc_mutex_lock(objc_mutex_t mutex)
{
- _objc_thread_t thread_id; /* Cache our thread id. */
+ objc_thread_t thread_id; /* Cache our thread id. */
int status;
if (!mutex) /* Is argument bad? */
* thread has a lock on the mutex returns -1.
*/
int
-objc_mutex_trylock(_objc_mutex_t mutex)
+objc_mutex_trylock(objc_mutex_t mutex)
{
- _objc_thread_t thread_id; /* Cache our thread id. */
+ objc_thread_t thread_id; /* Cache our thread id. */
int status;
if (!mutex) /* Is argument bad? */
}
/********
- * Decrements the lock count on this mutex by one. If the lock count reaches
- * zero, release the lock on the mutex. Returns the lock count on the mutex.
- * It is an error to attempt to unlock a mutex which this thread doesn't hold
- * in which case return -1 and the mutex is unaffected.
- * Will also return -1 if the mutex free fails.
+ * Decrements the lock count on this mutex by one. If the lock count reaches
+ * zero, release the lock on the mutex. Returns the lock count on the mutex.
+ * It is an error to attempt to unlock a mutex which this thread doesn't hold
+ * in which case return -1 and the mutex is unaffected.
+ * Will also return -1 if the mutex free fails.
*/
int
-objc_mutex_unlock(_objc_mutex_t mutex)
+objc_mutex_unlock(objc_mutex_t mutex)
{
- _objc_thread_t thread_id; /* Cache our thread id. */
+ objc_thread_t thread_id; /* Cache our thread id. */
int status;
if (!mutex) /* Is argument bad? */
return 0; /* No, return success. */
}
+/********
+ * Allocate a condition. Return the condition pointer if successful or NULL
+ * if the allocation failed for any reason.
+ */
+objc_condition_t
+objc_condition_allocate(void)
+{
+ objc_condition_t condition;
+
+ if (!(condition = (objc_condition_t)objc_malloc(
+ sizeof(struct objc_condition))))
+ return NULL; /* Abort if malloc failed. */
+
+ if ( pthread_cond_init(&(condition->condition), NULL) ) {
+ objc_free(condition);
+ return NULL;
+ }
+
+ return condition; /* Return condition handle. */
+}
+
+/********
+ * Deallocate a condition. Note that this includes an implicit
+ * condition_broadcast to insure that waiting threads have the opportunity
+ * to wake. It is legal to dealloc a condition only if no other
+ * thread is/will be using it. Here we do NOT check for other threads
+ * waiting but just wake them up.
+ */
+int
+objc_condition_deallocate(objc_condition_t condition)
+{
+ pthread_cond_broadcast(&(condition->condition));
+ pthread_cond_destroy(&(condition->condition));
+ objc_free(condition);
+ return 0;
+}
+
+/********
+ * Wait on the condition unlocking the mutex until objc_condition_signal()
+ * or objc_condition_broadcast() are called for the same condition. The
+ * given mutex *must* have the depth set to 1 so that it can be unlocked
+ * here, so that someone else can lock it and signal/broadcast the condition.
+ * The mutex is used to lock access to the shared data that make up the
+ * "condition" predicate.
+ */
+int
+objc_condition_wait(objc_condition_t condition, objc_mutex_t mutex)
+{
+ objc_thread_t thread_id; /* Cache our thread id. */
+
+ if (!mutex || !condition) /* Is argument bad? */
+ return -1; /* Yes, abort. */
+
+ thread_id = objc_thread_id(); /* Get this thread's id. */
+ if (mutex->owner != thread_id) /* Does some else own lock? */
+ return -1; /* Yes, abort. */
+ if (mutex->depth > 1) /* Locked more than once ? */
+ return -1; /* YES, return error */
+ /* mutex will be unlocked */
+ mutex->depth = 0; /* Yes, reset depth to 0. */
+ mutex->owner = (objc_thread_t) -1; /* Set owner to "no thread".*/
+
+ pthread_cond_wait(&(condition->condition),
+ &(mutex->mutex)); /* unlock, wait ..., lock */
+
+ mutex->owner = thread_id; /* Mark thread as owner. */
+ mutex->depth = 1; /* Increment depth to end. */
+ return 0; /* Return success. */
+}
+
+/********
+ * Wake up all threads waiting on this condition. It is recommended that
+ * the called would lock the same mutex as the threads in objc_condition_wait
+ * before changing the "condition predicate" and make this call and unlock it
+ * right away after this call.
+ */
+int
+objc_condition_broadcast(objc_condition_t condition)
+{
+ if (!condition)
+ return -1;
+ pthread_cond_broadcast(&(condition->condition));
+ return 0;
+}
+
+/********
+ * Wake up one thread waiting on this condition. It is recommended that
+ * the called would lock the same mutex as the threads in objc_condition_wait
+ * before changing the "condition predicate" and make this call and unlock it
+ * right away after this call.
+ */
+int
+objc_condition_signal(objc_condition_t condition)
+{
+ if (!condition)
+ return -1;
+ pthread_cond_signal(&(condition->condition));
+ return 0;
+}
+
/* End of File */
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